This invention generally relates to reclosable containers of the type having a cup and a removable lid; and more specifically, to containers of this type where the cup and the lid also form a seal along the connection between the cup and the lid when the lid is mounted on the cup.
Many food products are packaged and sold in reclosable containers of the type comprising a shell or cup and a lid or cap that can be removed from and then reconnected to the cup to repeatedly open and close the container. For example, cream cheese, cottage cheese, and other products are often packaged in this way.
Typically, the cup and the lid are both made of plastic and have well-defined, self-sustaining shapes, although both the cup and the lid are also slightly flexible. Normally, the cup and the lid are constructed so that when the lid is mounted in place on the cup, the flexibility and shape of the cup and the lid cooperate to hold the lid in place until a small force is intentionally applied to the lid to remove it from the cup. In use, a consumer removes the lid to open the container, removes a portion of the food product therein, and then replaces the lid to reclose the container, thereby to help maintain the freshness, taste, and aroma of the food product remaining in the container.
These containers are usually designed to accomplish several objectives simultaneously. For example, the containers are often designed so that an effective hermetic seal is formed between the lid and the cup when the lid is mounted on the cup to close the cup. This seal may be achieved by designing the lid and the cup so that when the lid is connected to the cup, the lid and cup are in pressure engagement along a line or small area extending completely around the connection or interface between the cup and the lid.
This, in turn, may be done, for example, by providing the cup with a small bead or lip extending around the perimeter of the cup, and by providing the lid with a small groove extending around the perimeter of the lid and adapted to receive the bead or lip of the cup. As the lid is placed on the cup, the lid and cup flex slightly, allowing the groove on the lid to slide toward the bead on the cup. The lid is moved further along the cup to slide the bead into the groove; and as this happens, the inherent resiliency of the lid and the cup cause the lid and cup to flex back, with the bead extending into the groove, in pressure engagement with the surfaces of the lid forming that groove. This pressure engagement may form the desired seal between the cup and the lid, or this engagement may be used to hold other, adjacent portions of the lid and cup together to form the desired seal.
The above-described connection between the lid and the cup also tends to hold the lid firmly on the cup. This helps to prevent the container from being opened accidently or inadvertently during normal handling of the container or in case the container is dropped.
Containers of the above-described type are also normally designed so that the lid can be repeatedly removed from and then reconnected to the cup, and this usually requires that the lid be relatively rigid. If the lid is not rigid, repeated handling of the lid may tear or deform the lid, particularly in view of the above-described firm pressure engagement between the lid and the cup.
In addition, containers of this type are commonly designed so that several containers can be stacked on top of each other. This facilitate storing and shipping the containers, as well as displaying the containers in a store or market. In order to achieve this objective, the cup or shell of the container may be made from a relatively strong, rigid material.
These prior art containers also usually have one or more thin membranes that contain printed information. This printed information may, inter alia, identify the name of the food product and the name of the manufacturer, and a membrane may be glued or molded to the lid or the cup of the container. Typically, these membranes do not serve any mechanical function.
The above-outlined design considerations sometimes conflict with each other. For instance, as previously mentioned, in order to ensure that the lid may be repeatedly removed and reconnected to the cup, it is preferred to form the lid from a relatively rigid material. In addition, in order that a multitude of containers be stacked one on top of another, it is also preferred to form the cups of the containers from a relatively rigid and thick material.
However, in order to develop a good seal between the cup and the lid, it is preferred to form the cup and lid from a more flexible material. In this way, the areas of the cup and lid that are pressed against each other to form the seal can closely conform to and fit against each other despite any small irregularities or imperfections in or on those areas. Because of these conflicting considerations, the final design of the container is a compromise.